Blender Freestyle - how to make line crossings glow more than lines themselves?
You can use a blur node to get this effect.
The blurred lines will overlap a bit at the intersections, making them brighter.

For example:


Create a renderlayer which only renders freestyle lines by disabling everything else in Render layers > Layer > Include:


Set the freestyle line color to white in Render layers > Freestyle Line Style:


Composite (click for larger image):




Result (click for html5 version):